The present invention relates generally to superconductor circuits, and more specifically the invention pertains to a superconductor receiver that includes a lens and planar antenna, pre-amplifier, mixer, local oscillator, and IF amplifier on a single silicon chip.
Surveillance and communication at terahertz frequencies requires advanced technologies to achieve high sensitivities necessary for system performance. Ultimately heterodyne receivers in space will be called upon to approach the fundamental physical limits imposed by the cosmic blackbody radiation and quantum photon noise.
High frequency receivers (greater than 45 GHz) are important for wideband communications, radar, and other remote sensing applications. Current receivers are bulky, insensitive, power-hungry, not monolithic, and incompatible with focal plane arrays.
The spectral region from 50-1000 GHz has applications for passive and active surveillance, and secure, widebanked space communications. Previous exploitation of this band has been nearly impossible because of a lack of device technology. Superconductive electronics based on Josephson junctions incorporated into monolithic or hybrid integrated circuits can provide an entire set of electronic devices and components which will operate from microwave to terahertz frequencies. The fundamental nonlinear properties of the Josephson junction permit development of voltage-controlled oscillators, low noise amplifiers, and coherent detectors over the terahertz frequency band. Ultra low loss exhibited by superconductive transmission lines can be integrated with active superconductive components to achieve efficient, high performance, terahertz circuits.
The task of providing a superconductive, high frequency receiver is alleviated, to some extent, by the systems disclosed in the following U.S. Patents, the disclosures of which are incorporated herein by reference:
U.S. Pat. No. Re 32,639 issued to Stockton et al;
U.S. Pat. No. 4,070,639 issued to Nemit et al;
U.S. Pat. No. 4,490,721 issued to Stockton, et al;
U.S. Pat. No. 4,617,528 issued to Bert et al;
U.S. Pat. No. 4,731,614 issued to Crane;
U.S. Pat. No. 4,823,136 issued to Nathanson et al;
U.S. Pat. No. 4,839,712 issued to Mamodaly et al;
U.S. Pat. No. 4,904,831 issued to Nathanson et al; and
U.S. Pat. No. 4,967,201 issued to Rich, III.
Stockton et al (U.S. Pat. No. Re 32,369 and U.S. Pat. No. 4,490,721) disclose a monolithic microwave integrated circuit including an integrated array antenna. The system includes radiating elements, feed network, phasing network, active and/or passive semiconductor devices, digital logic interface circuits, and a microcomputer controller simultaneously incorporated on a single semi-insulating GaAs substrate by means of a controlled fabricating process sequence. Several embodiments are disclosed (although we note that a heat sink is not disclosed).
Crane discloses a phased array system having a circulator, a transmitter connected to the circulator, a receiver connected to the circulator, a receiver/transmitter IF distribution network connected to the circulator, M phase shifters connected to the receiver/transmitter IF distribution network, a local oscillator, a local oscillator distribution network, N phase shifters, and an orthogonal array of M.times.N transmitting/receiving means. Each of the receiving means comprises an IF mixing diode connected to one of the M-phase shifters and N-phase shifters. M.times.N antennas are individually connected to the mixing diodes. The phased array system has plural dielectric layers. A heterodyne or mixing process preserves the phase.
The two Nathanson et al references disclose a transmit-receive means for a phased-array active antenna system using redundancy. Each transmit-receive cell comprises a multiplicity of electronic devices implanted on a common semiconductor substrate. Each transmit-receive means or duplexer comprises an attenuation means, a phase-shifting means, a multistage amplification means, a low-noise amplification means, and appropriate transmit-receive switches. Heat sinks are provided.
Rich, III discloses a multi-layer single substrate microwave transmit/receive module wherein the substrate has at least two opposing mounting surfaces and a plurality of integrated dielectric layers mounting a microwave signal processing means, a control signal processing means, a power conditioning means, and a heat sink interface.
While the above-cited references are instructive, there remains a need to provide a superconductive receiver that receives, down converts, and processes high frequency (50-1,000 GHz) radio frequency signals. The present invention is intended to satisfy that need.